While we technically have enough multi-author worlds to run a small poll, I would dearly love to get a few more nominations before we begin. It's not that I don't love six item polls but....okay yes it is that.
(Insert joke about liking big long polls here. Snerk snerk.)
Any world in which multiple authors have written different published books is viable. That means no collaborative books (that'll be next month) and no fan fiction, but everything from various scifi franchises "extended universes" (like the Star Trek books or Star Wars books) to Dungeons and Dragons worlds (I'm surprised no one has nominated Krynn yet) to worlds like Asimov's Foundation universe are all up for the nominating.
Head over to the original nomination page to check out the rules, second an existing nomination to cinch its place in the poll, or pony up a couple of choice worlds. Please do it over there rather than here so that everything is in one place. I have about four working brain cells right now. No sense overtaxing them.